The invention relates to an improved apparatus for conditioning an article, such as an envelope, having a bentover flap. More particularly, the invention relates to an improved apparatus for opening envelopes at rates compatible with high speed serial feeding of opened envelopes to a work station.
In conventional high volume mailrooms utilizing document inserting apparatus, envelopes are delivered to a work station in opened condition and arranged so that sheets or documents may be inserted into the envelope. Thus, the envelopes, which are typically furnished by the manufacturer with the flap folded firmly against the body, must be serially opened individually and then serially fed to the work station with the flap bent back so as to permit access to the interior of the envelope. Conventional envelope-opening devices have worked well in relatively slow mailing systems, but in order to continue to meet mailing deadlines as the volume of mail increases it has become necessary to substantially increase the throughput of the envelope conditioning apparatus.
U.S. Pat. No. 2,668,053 issued to Bach discloses a two-cycle envelope-opening device in which an envelope is fed edgewise in a first direction, flap edge foremost, along a curved path into abutment against a stop positioned such that the flap passes beyond a stripper plate and then in a second, oppositely-directed movement is fed past the stripper plate which then engages the flap and folds it back as the envelope moves by. This device works well at slower speeds but because of the paper paths which must be sequentially negotiated by the envelopes, any jams which occur normally involve at least two envelopes so that they are difficult to clear and, since the envelope must come to a complete stop and then reverse direction during the cycle, the possibilities for increased speed are limited. A further nuisance in such prior devices is that two cycles must occur before proper insertion of documents into an envelope is re-established.
U.S. Pat. No. 3,162,435 issued to Rastorguyeff, et al. addressed and solved some of the problems mentioned above by utilizing a different technique for opening envelope flaps. In this device a flap-intercepting nose of a pivoted member is driven toward the envelope body by the force of the lower edge of the envelope striking a lever arm of the member as the enveloped is transported around a transfer roller. The feeding movement of the envelope against the lever arm causes this nose to slideably engage and fold back the flap. While this device has also worked well at low speeds, it cannot be easily adjusted to accommodate the various thicknesses and stiffnesses of the envelopes available. An even more significant limitation has been found in that in high speed operation using such devices, instances have occurred where the flaps of envelopes have been completely sheared off, apparently because of the increased engaged force of the intercepting edge created by particular combinations of envelope thickness and speed.
A solution to the problems described above is found in U.S. Pat. No. 4,715,164 assigned to the assignee of the instant application, where a high-speed flap-opening device is used in combination with a relatively large transfer roller having two spaced rollers disposed along the periphery thereof to form two separated nips. The pivotable envelope flap-opener includes a guide having a lip for engaging the flap of the envelope and is disposed in a first position for receiving an envelope from the first nip. The force of the envelope causes the flap-opener to pivot to a second position which guides the envelope to the second nip. As the flap emerges from the first nip, the lip of the flap-opener engages the flap to bend it back as the envelope passes through the second nip.
Experience with the flap-opener of the '164 patent has shown that the flap-opener is subjected to considerable forces and inertia resulting from constant pivoting, and that owing to the considerable mass of the flap-opener, that long-term viability of the device is not optimal. The instant invention provides a flap-opening device which utilizes a pair of guides disposed adjacent the periphery of a transfer roller which are subjected to less force than the flap-opener of the '164 patent and hence a longer life span of the device is achieved.